Fix kernel counter creation error detection

kernel/sched/perf_error_detection.c

@@ -38,7 +38,7 @@ int init_perf_event(
 			NULL);
 	local_irq_restore(irq_flags);
 
-	if (IS_ERR(pevent)) {
+	if (IS_ERR(*pevent)) {
 			printk(KERN_WARNING "PB ERROR INITIALISING PERF EVENT\n");
 			return -1;
 	}